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- Cho, C. R., et al.
(author)
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Ferroelectric Na0.5K0.5NbO3 thin films by pulsed laser deposition
- 2000
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In: Integrated Ferroelectrics. - : Informa UK Limited. - 1058-4587 .- 1607-8489. ; 31:1-4, s. 35-45
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Journal article (peer-reviewed)abstract
- Highly c-axis oriented single phase Na0.5K0.5NbO3 (NKN) thin films have been deposited onto polycrystalline Pt80Ir20 substrates and SiO2/Si(001) wafers using pulsed laser ablation of stoichiometric ceramic target. Strong self-assembling of NKN films along the [001] direction has been observed. Properties of NKN/Pt thin film structures have been successfully tailored by oxygen pressure control from the ferroelectric state, characterized by the remnant polarization of 12 muC/cm(2), dielectric constant epsilon similar to 520 and tan delta - 0.024 @ 100 kHz, to superparaelectric state with tan delta as low as 0.003 and epsilon = 210 with very small 1.7% dispersion in the frequency domain 0.4-100 kHz and less than 10% Variation in the temperature range 77-415 K. NKN films grown onto SiO2/Si(001) substrates show quadrupled super-lattice structure along c-axis, loss tan delta less than 0.01, and epsilon similar to 110 @ 1 MHz. C-V measure ments for Au/NKN(270nm)/SiO2/Si MFIS-diode structure yield memory window of 3.26 V at the programmable voltage of 8 V.
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- Cho, C. R., et al.
(author)
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Na0.5K0.5NbO3 thin films for MFIS_FET type non-volatile memory applications
- 2002
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In: Integrated Ferroelectrics. - 1058-4587 .- 1607-8489. ; 49, s. 21-30
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Journal article (peer-reviewed)abstract
- Na0.5K0.5NbO3(NKN) thin films have been prepared on Pt80Ir20, SiO2/Si, and Ta2O5/Si substrates for ferroelectric non-volatile memory applications. Ferroelectric hysteresis loops for Au/NKN/Pt80Ir20 vertical capacitor yielded remnant polarization of 12 muC/cm(2) and coercive field similar to20 kV/cm. Significant flat-band voltage V-FB shifts with buffer layer thickness in Au/NKN/SiO2/Si structures have been attributed to the intermixing between Na and K alkali ions and SiO2 layer. On the other hand, Au/NKN/Ta2O5/Si structure exhibited wide memory window without significant V-FB deviations, low leakage currents, and rather long retention time at zero bias.
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- Shepherd, R., Audebert, P., Chen, H-K, Fournier, K.B., Peyreusse, O., Moon, S., Price, D., Klein, L., Gaithier, J.C., Springer, P., Lee, R.W.
(author)
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Satellite and opacity effects on resonance line shapes produced from short-pulse laser heated foils.
- 2003
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In: J. Quant. Spectroscopy & Radiative Transfer. ; 81
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Other publication (other academic/artistic)
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- Thinh, N. Q., et al.
(author)
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Identification of Ga-interstitial defects in GaNyP1−y and AlxGa1−xNyP1−y
- 2004
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In: Physical Review B. Condensed Matter and Materials Physics. - : APS. - 1098-0121 .- 1550-235X. ; 70:12, s. 121201-
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Journal article (peer-reviewed)abstract
- Two Ga -interstitial (Gai) defects are identified by optically detected magnetic resonance as common grown-in defects in molecular beam epitaxial GaNyP1−y and AlxGa1−xNyP1−y. Characteristic hyperfine structure arising from spin interaction between an unpaired electron and a Ga nucleus is clearly resolved. The observed strong and nearly isotropic hyperfine interaction reveals an electron wave function of A1 symmetry that is highly localized at the Gai and thus a deep-level defect. Our analysis based on first-principles calculations suggests that these defects are complexes containing one Gai2+ .
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